A large number of organic electroluminescence (EL) devices each using an organic substance have been developed because of their potential to find applications in solid light emission type, inexpensive, large-area, full-color display devices. In general, an organic EL device is constituted of a light emitting layer and a pair of opposing electrodes between which the layer is interposed. Light emission is the phenomenon in which when an electric field is applied between both the electrodes, an electron is injected from a cathode side and a hole is injected from an anode side, and, further, the electron recombines with the hole in the light emitting layer to produce an excited state, and energy generated upon return of the excited state to a ground state is emitted as light.
A conventional organic EL device was driven at a voltage higher than the voltage at which an inorganic light emitting diode is driven, and had emission luminance and luminous efficiency lower than those of the diode. In addition, the properties of the device deteriorated remarkably, so the device has not been put into practical use. A recent organic EL device has been gradually improved, but actually, additionally high luminous efficiency and an additionally long lifetime of the device are still requested.
As a conventional organic light emitting material, for example, a single monoanthracene compound (see Patent Document 1) and a single bisanthracene compound (see Patent Document 2) are disclosed. In addition, a technique for a long-lifetime organic EL device obtained by adding, for example, styrylamine to a distyryl compound to be used as an organic light emitting material is proposed (see Patent Document 3).
In addition, a technique involving the use of each of a monoanthracene or bisanthracene compound and a distyryl compound in an organic light emitting medium layer is disclosed (see Patent Document 4).
Further, a blue light emitting device using a diaminochrysene derivative is disclosed (see Patent Document 5). In addition, an invention in which an aromatic amine derivative having an arylene group at its center is used as a hole transporting material (see Patent Document 6), an invention in which an aromatic amine derivative where a dibenzofuran ring, a dibenzothiophene ring, a benzofuran ring, a benzothiophene ring, or the like is bonded to a nitrogen atom through an arylene group is used as a hole transporting material (see Patent Document 7), and the like are also disclosed. In addition, an invention in which an aromatic diamine derivative where a phenyl group having a substituted or unsubstituted silyl group substitutes for a nitrogen atom is used as a material for a light emitting layer (see Patent Document 8) is disclosed.
Patent Document 1: JP 11-3782 A
Patent Document 2: JP 08-12600 A
Patent Document 3: WO 94/006157 A1
Patent Document 4: JP 2001-284050 A
Patent Document 5: WO 04/044088 A1
Patent Document 6: JP 3508984 B2
Patent Document 7: WO 07/125,714 A1
Patent Document 8: WO 07/108,666 A1